N-oxidation process for amino-polymers

ABSTRACT

The present invention relates to a process for the N-oxidation of polyamine polymers comprising treating said polyamine polymers with an effective amount of hydrogen peroxide in an aqueous or partly aqueous solution in the presence of heavy metal ion sequestrant and a metal oxide catalyst selected from tungstate, molybdate and vanadate.

EXAMPLES Example 1

In a process in accord with the invention 1 part poly L-histidine (ex Sigma) was added to a solution of:

0.07 parts sodium tungstate (ex Merck(TM))

0.24 parts *DTPMP solution (26% active)

and 4.43 volumes hydrogen peroxide solution (30% w/v ex Merck(TM))

The pH of the mix was adjusted from approx. 7 to approx. 6 with hydrochloric acid (15% w/w) and the resultant mix heated to 60-65 deg. C (when all the solid dissolved) and held for 4 hours.

Testing with starch/potassium iodide paper indicated excess peroxide still present and the pH was found to have fallen to approx. 4.

The pale yellow solution was added, with agitation, to acetone (200 volumes) to precipitate a white solid which was filtered off, washed and dried.

The dried solid was redissolved in water (4.7 volumes) and the pH adjusted from approx. 5 to approx. 1-2 (with conc. hydrochloric acid) when a white, gelatinous precipitate formed. This was removed by filtration and the filtrate added, with agitation, to acetone (200 volumes) to re-precipitate the N-oxidised product, which was filtered, washed and dried.

Proton nmr analysis confirmed the product to be essentially 100% N-oxidised product.

Example 2

In a process in accord with the invention 10 parts poly 4-vinylpyridine 10% solution in 50:50 t-butanol/water (ex Cassella(TM)) from the polymerisation process were added to a solution of:

0.08 parts sodium tungstate (ex Merck(TM))

0.36 parts *DTPMP solution (26% active)

3.43 volumes hydrogen peroxide soln. (30% w/v ex Merck (TM))

The pH of the solution was adjusted from 7.1 to 5.4 (with conc. hydrochloric acid) and the mix refluxed for 2 hours when a pale yellow viscous oil separated. This was dissolved by the addition of a further 3.43 volumes of 30%w/v hydrogen peroxide solution and the mix was refluxed a further 2 hours.

After cooling the solution was added, with agitation, to acetone (200 volumes) when a viscous yellow syrup separated. The supernatant liquors were decanted and the syrup further treated with acetone to form a pale yellow solid, which was filtered, washed and dried in vacuo.

Proton nmr analysis indicated 80 mole% N-oxidised product.

Example 3

In a process in accord with the invention 1 part poly 4-vinylpyridine (solid ex Cassella(TM)) was added to a solution of:

0.086 parts sodium tungstate

0.36 parts *DTPMP solution (26% active)

5.7 volumes hydrogen peroxide solution (30% w/v ex Merck (TM))

1.9 volumes ethanol.

The mix was held at 60-65 deg C for 4 hours then allowed to cool before adding to acetone (200 volumes) to precipitate a pale yellow solid. The solid was isolated by filtration, washed with acetone and dried under vacuum.

Proton nmr analysis indicated >90 mole% N-oxidised product.

Example 4

In a process in accord with the invention a solution of:

0.08 parts sodium molybdate dihydrate (ex Merck(TM))

0.095 parts ethylene diamine tetra acetic acid, disodium salt (ex Merck(TM))

5.71 volumes hydrogen peroxide solution (30% w/v ex Merck (TM))

5.71 volumes ethanol was made up and to this dark red solution was added:

1.0 part poly 4-vinylpyridine (solid ex Cassella(TM))

The mix was heated to 60-65 deg C when the solid dissolved to form a red solution of pH approximately 6-7.

After 1.5 hours at 60-65 deg C the red colour had faded to pale yellow and a further aliquot (2.86 volumes) of hydrogen peroxide solution was added.

Further aliquots (2.86 volumes each) of hydrogen peroxide solution were required after another 45 minutes, then another 60 minutes to regenerate the reddish colour.

After a total of 4.25 hours at 60-65 deg C in the presence of the red species, the solution (pH approximately 6) was cooled and added, with agitation, to acetone (150 volumes). The supernatant liquors were decanted and the residual yellow sticky solid was re-slurried in acetone, gravity filtered, washed with acetone and dried in vacuo.

270 MHz proton nmr analysis indicated 81 mole % yield of N-oxidised product. 

We claim:
 1. A process for the N-oxidation of polyamine polymers comprising treating said polyamine polymers with an effective amount of hydrogen peroxide in an aqueous or partly aqueous solution in the presence of heavy metal ion sequestrant and a catalytic amount of metal oxide catalyst selected from tungstate, molybdate and vanadate.
 2. A process according to claim 1 wherein said polyamine polymers contain units having the following structural formula: ##STR1## wherein P is a polymerisable unit, whereto the oxidisable N atom can be attached, or wherein the oxidisable N atom forms part of, the polymerisable unit.A is ##STR2## x is or 0 or 1; R are aliphatic, ethoxylated aliphatic, aromatic, heterocyclic or alicyclic groups whereto the oxidisable N atom can be attached, or wherein the oxidisable N atom is part of, these groups.
 3. A process according to claim 1 wherein said polyamine is present at a level of from 1% to 40% by weight of said aqueous or partly aqueous solution.
 4. A process according to claim 1 wherein said metal oxide catalyst is present at a level of from 0.001% to 2% by weight of said aqueous or partly aqueous solution.
 5. A process according to claim 1 wherein said heavy metal ion sequestrant is selected from polycarboxylate or polyphosphonate heavy metal ion sequestrants and is present at a level of from 0.005% to 2% by weight of said aqueous or partly aqueous solution.
 6. A process according to claim 1 wherein said partly aqueous solution comprises an alcohol selected from methanol, ethanol, n-propanol, n-butanol, t-butanol and any mixtures thereof.
 7. A process according to claim 1 wherein said process is carried out at a temperature of from 30° C. to 100° C. and at a pH of from 1 to
 10. 8. A process according to claim 2 wherein P is a polymerisable unit wherein the oxidisable N atom is attached to and wherein R is selected from an aromatic or heterocyclic group.
 9. A process according to claim 8 wherein the oxidisable N atom forms part of a heterocyclic R-group.
 10. A process according to claim 9 wherein the heterocyclic R-group is selected from pyridine, imidazole and derivatives thereof.
 11. A process according to claim 2 wherein the oxidisable N atom is attached to the R-group.
 12. A process according to claim 11 wherein R is a phenyl group.
 13. A process according to claim 2 wherein P is a polymerisable unit, whereto the oxidisable N atom forms part of the polymerisable unit and wherein R is selected from an aromatic or heterocyclic group.
 14. A process according to claim 13 wherein the oxidisable N atom forms part of the R-group.
 15. A process according to claim 14 wherein the R-group is selected from pyridine, imidazole and derivatives thereof.
 16. A process according to claim 2 wherein the polymeric backbone is derived from the group of the polyvinyl polymers. 